krpano is a small and very flexible high-performance software for showing all kind of panoramic images on the web. It can be used for very detailed high-resolution images, for interactive virtual tours, custom designed user-interfaces and many things more.
The order is as follows: 1) upload to the site spherical panoramas from which you plan to create a virtual tour; 2) from the list of uploaded panoramas add each panorama to the virtual tour (Add to 3D tour link); 3) open the created virtual tour, edit the panorama order, select the main panorama, set transition points (tunnels).